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  • Pre Built X O Question

    Most the post I read about prebuilt XO's are bad, all advice is to stay away from them. My question is why does P E or madisound or other places sell them then? Another question, I have some old speakers that I just wanna put to good use ( never hardly throw anything away), I dont want to put a lot into designing a XO,(dont know how and it looks like more than I can grasp unless I put countless hours into learning) so what is the harm in buying a prebuilt? If anyone answers positivley to this then whats the best method to match Xo;s to speakers that I know nothing about? What I have is basicly 2 cheap 4" woofers 2 4" midranges and 2 1" tweeters whats the best prebuilt Xo for these? I know there are gonna be some who want me to build my own, but I dont have the time to learn right now, and not to be sarcastic, just dont have the want to, to learn how to build my own. By the way I read these post daily and enjoy it very much, and want to say thanks for all the good reading.

  • #2
    Re: Pre Built X O Question

    Pre-built crossovers could work ok with extremely well behaved drivers, but since you know nothing about what you have it would basically be a shot in dark. Odds are it would sound horrible and you would be wasting your time.

    Madisound sells a several kits will pre-built crossovers specific to the speaker so I would check those out.

    Personally I don't think PE should be selling generic pre-built crossovers.

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    • #3
      Re: Pre Built X O Question

      all speakers seem to have strong points and week points. when measured, these points can be tamed or enhanced.
      that being said, you, at mininum, you must identify the speakers you have and get a crossover that is appropiate. they might sound fine to you at first, but they will allow you to learn why its not the best way to go. if the woofer is full range you might get away with some protection for the tweeter. its a cheap way to learn. under 20 for the cheap x-overs twice that for the better ones. good luck.
      bytheway. the reccession busters at madisound are a pair for 60 bucks.
      " To me, the soundstage presentation is more about phase and distortion and less about size. However, when you talk about bass extension, there's no replacement for displacement". Tyger23. 4.2015

      Quote Originally Posted by hongrn. Oct 2014
      Do you realize that being an American is like winning the biggest jackpot ever??

      http://www.midwestaudioclub.com/spot...owell-simpson/
      http://s413.photobucket.com/albums/pp216/arlis/

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      • #4
        Re: Pre Built X O Question

        Hey Arlis, thanks. I do have the RB from madisound and the Destroyers from PE. Got the RB done and love em havent gotten to the Destroyers yet. I did find out that the cheap speakers I have are 6 ohm. Does that mean I need a 6 ohm crossover? I got my head set on trying a prebuilt crossover. Sorry for all the people on here who think I am wasting my time and I should build my own. I just gotta experiment, thats how I learn.:D

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        • #5
          Re: Pre Built X O Question

          A pre-built XO can work with a 2-way provided you choose the right drivers to pair it with, but it will not work at all for a 3-way speaker. A 3-way simply has too many variables involved and a pre-made "textbook" crossover takes none of these into account.

          The reason pre-made crossovers don't work is because they assume "textbook" drivers, which are imaginary. A textbook driver has ruler-flat frequency response and ruler-flat impedance, and doesn't take in the effects of the cabinet/box into consideration at all. Real drivers have large peaks and dips in the response curve, as well as peaks and rising impedance curves, which change the way the crossover works. The other thing that premade crossovers don't consider at all is the effect of baffle-step response. Basically this is a loss of bass/midrange when you mount a speaker inside a box, determined by how wide the box is. Even if a premade crossover worked with the drivers you chose, it would not address this loss of midrange/bass energy and the speaker will sound very harsh, bright, and thin.

          I wrote a quick article on how to design your own crossovers here:
          http://techtalk.parts-express.com/sh...d.php?t=210439

          Once you get the hang of it it's not that difficult, and you'll see how specialized the filters need to be. It's not an issue of being "close enough," a premade crossover simply 95% of the time will be way, way off what you think it's going to do, and ends up being a waste of your time, because if you spend all this time making the cabinet and putting it all together, you chould spend an extra 30 minutes soldering your own crossover so that you actually get good sound at the end

          But if you must, go ahead and try it! I can guarantee you the 3-way will sound terrible, try a 2-way for your first project (woofer and tweeter, skip the midrange).

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          • #6
            Re: Pre Built X O Question

            Originally posted by dogwreck View Post
            Hey Arlis, thanks. I do have the RB from madisound and the Destroyers from PE. Got the RB done and love em havent gotten to the Destroyers yet. I did find out that the cheap speakers I have are 6 ohm. Does that mean I need a 6 ohm crossover? I got my head set on trying a prebuilt crossover. Sorry for all the people on here who think I am wasting my time and I should build my own. I just gotta experiment, thats how I learn.:D
            If you want to experiment, try a series crossover. Here's a link to some information, thanks to Andy G.

            http://members.optusnet.com.au/~grad...oss-overs1.htm

            and a series / parallel comparison article from Rod Elliott:

            http://sound.westhost.com/parallel-series.htm

            These are simple and easy to calculate and implement. You will learn far more this way than simply trying a prebuilt crossover, and the results will be far more satisfying.

            C
            Curt's Speaker Design Works

            "It is the mark of an educated mind to be able to entertain a thought without accepting it."
            - Aristotle

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            • #7
              Re: Pre Built X O Question

              Hi Dog
              I agree with everyone here. It's really a learning experience and a discovery process. In that sense and since you are just starting maybe it's OK to spend a few bucks on a pre-made just as a bass-line. As you read and learn you can try things and hear the difference. I would suggest:

              1. Go with a small 2-way especially with the drivers you have. This will cover everything above 80-100 Hz. Then when you're happy with the sound you can build a Subwoofer for your next project!

              2. You need to try to find T&S parameters for the woofer. At least Fs to get the box size and tuning in the ball park. Tell us what they are maybe someone here has some info. Measuring the parameters yourself is probably not practical at this stage

              3. Build the box and run the wires from both tweeter and woofer out the back and seal with caulk or dum-dum to make it airtight. This way you can work on the x-over outside the box and quickly hear the results as you make changes.

              4. Connect the pre-built x-over which will at least protect the tweeter from damage by keeping the low frequencies out.

              5. Set up a work station with a small amp and cd player to get you started with some critical listening. Ideally make it so you can leave it set up all the time. It helps to walk away and come back later or the next day to see if you still hear the same things. The more you listen the more you will hear but it's easy for your ears to get stale and fatiqued. Try to have a reference system that you trust. Your main system, a friend's, Stereo shop are all good comparison opportunies to help you develop a critical ear.

              6. Read all the good advice here to learn about identifying all the different undesirable distortion and inaccuracies and what to do about it.

              Have fun. If it starts to become a hassle just walk away.

              CC

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              • #8
                Re: Pre Built X O Question

                Originally posted by dogwreck View Post
                Hey Arlis, thanks. I do have the RB from madisound and the Destroyers from PE. Got the RB done and love em havent gotten to the Destroyers yet. I did find out that the cheap speakers I have are 6 ohm. Does that mean I need a 6 ohm crossover? I got my head set on trying a prebuilt crossover. Sorry for all the people on here who think I am wasting my time and I should build my own. I just gotta experiment, thats how I learn.:D

                It's not just a matter of time that's wasted, which is valuable in itself, but the $$ that is wasted on trying to get something to work that by others accounts, cannot because of the many variables at work. I tried for years to get good results with pre-made XO's, even tweaking them. Always lousy results. I tried textbook-formula alignments, same thing, not even acceptable. I couldn't figure out why the "math" wasn't working. I had a pair of Speakerlab S2's, which I built in 1977, that embarrassed commercial offerings, so I had a reference point. Plus, with 20 years of working at a high-end audio emporium, I knew what a decent speaker should sound like. I never got anywhere near acceptable SQ with any pre-made or textbook formulas. I found this forum over 9 years ago, and with the kind and generous help and advice, I finally realized why those XO's weren't working...the same opinions and advice that's being offered now. I don't like to think of the money I spent trying pre-mades and textbook XO's. Not to mention the value of all that time trying to make 'em work. At this stage, you don't have to design a XO on your own, as there are many fine projects that you can build that will help your learning curve and understanding of what goes into a proper XO design. Jeff Bagby has the excellent PCD 6.20, which uses measured data for designing a XO if you want to "roll your own".

                http://audio.claub.net/software/jbagby.html

                Learning curve is easier than most freeware programs, and some of the guys here use it, so help is available. Take it from an old speaker hack, I wish I'd had the advantage of the wealth of knowledge I found here 20 years ago. I'd have saved enough money to get the electronics I really want and build a pair of Wayne & Curt's Statements, with $$ to spare.

                John A.
                "Children play with b-a-l-l-s and sticks, men race, and real men race motorcycles"-John Surtees
                Emotiva UPA-2, USP-1, ERC-1 CD
                Yamaha KX-390 HX-Pro
                Pioneer TX-9500 II
                Yamaha YP-211 w/Grado GF3E+
                Statement Monitors
                Vintage system: Yamaha CR-420, Technics SL-PG100, Pioneer CT-F8282, Akai X-1800, Morel(T)/Vifa(W) DIY 2-way in .5 ft3
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                Blogs: http://techtalk.parts-express.com/blog.php?u=2003

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